To make a magnetic disk unit compact and thinned so that it may be used as a portable and exchangeable storage medium, an internal spindle mechanism, a magnetic head positioning mechanism and so on must be protected from impacts that result from falls or the like of the magnetic disk unit.
For example, Japanese Unexamination Patent Publication No. 5-258545 discloses a magnetic disk unit in which a viscous member is sandwiched between a base and a top plate to absorb vibrations of its cover. However, the disclosure fails to propose any solution to avoid an adverse effect caused to a spindle motor and a head positioner by impacts exerted to the base plate.
Further, Japanese Unexamination Patent Publication No. 4-368690 discloses a magnetic disk unit in which the four external corners of the case of the unit are provided with elastic members so as to weaken impacts caused when the unit falls and hits against a floor. However, the disclosure has proposed no solution to cope with impacts exerted to the unit at its portions other than the four corners.